en_tn_lite_do_not_use/mat/17/15.md

have mercy on my son

It is implied that the man wants Jesus to heal his son. AT: "have mercy on my son and heal him" (See: rc://en/ta/man/translate/figs-explicit)

is epileptic

This means that he sometimes had seizures. He would become unconscious and move uncontrollably. AT: "has seizures"